The quantitative determination of analytes in body fluids is of great importance in the diagnoses and maintenance of certain physiological abnormalities. For example, blood glucose, hemoglobin (Hb), hemoglobin A1C (HbA1c), lactate, cholesterol, bilirubin, and other analytes should be monitored in certain individuals. In particular, it is important that individuals who are diabetic frequently check the glucose level in their body fluids to regulate the glucose intake in their diets. The results of these analyte tests may be used to determine what, if any, insulin or other medication should be administered.
In one type of testing system, test sensors are used to test a fluid, such as a sample of blood. The test sensor contains biosensing or reagent material that will react with the analyte of interest, such as blood glucose. The testing end of the test sensor is adapted to be placed into the fluid being tested, for example, blood that has accumulated on a person's finger after the finger has been pricked. A sufficient amount of fluid to be tested is drawn by capillary action into a capillary channel that extends in the test sensor from the testing end to the reagent material. In some test sensors, the fluid then chemically reacts with the reagent material in the test sensor resulting in an electrical signal indicative of the analyte level in the fluid being tested.
One problem with current test sensors is that the reagent material may contain components that produce an undesirable background current or signal. The background current may affect the accuracy and precision of the testing results, as well as the stability of the testing system. The background current may result from impurities in the components of the reagent or from the components themselves. Thus, it would be desirable to have a test sensor reagent that improves test sensor accuracy, precision and stability by reducing the background current. Furthermore, by reducing the background current, at least one of the parameters (i.e., the intercept value) involved in the calibration process may be reduced or eliminated which will reduce the effort necessary to provide calibration information for a particular lot of test sensors and will be beneficial to users who will have less information to input for calibration purposes.